Lubricating composition



Patented Mar. 25, 1947 LRICATING COMPOSITION William A. Jones, PoncaCity, Continental Oil Company, corporation of Delaware kla., assignor toPonca City, Okla., a

Serial No. 57 9,319

8 Claims.

This application relates to application No. 466,945, filed November 25,1942, now pending before the Patent Oflice. This invention relates tolubricating compositions adapted for use under service conditionsinvolving high temperature and severe oxidation conditions.

In order to provide satisfactory lubrication of engine parts of engineoperating under severe conditions of high temperature and high poweroutput, it has been found necessary to use highly refined mineral oillubricants. These highly refined mineral oil lubricants, usuallyobtained by solvent treating, have a reduced tendency to change inviscosity with temperature changes and to form oxidation productsinsoluble in the oil while in service.

Some of the difiiculties which have been encountered in their use,however. are their tendency to oxidize to form oil soluble organic acidswhich cause corrosion on the metal parts of the en ine, particularly thesensitive bearing materials commonly used in heavy-duty service. Thesespecific materials when exposed to engine parts at hi h temperature formcondensation products which result in lacquer-like products whichinterfere with the proper operation of the en ine.

A further undesirable feature of these hi hly refined lubr catin oils istheir inab lity to carry in su ension extraneous material introducedinto the crankcase from some outside source, such as soot and lead fromthe combustion chamber and dirt and dust from the atmosphere. Thiscauses the collection of deposits in various portions of the engine whch prevents its proper operation. Because of these conditions a largenumber of addit on a ents have been incorporated in the blends of highlyrefined mineral oil in order to alleviate these difiiculties.

One class of these addition agents is materials contain n phosphorus orsulfur or both. These materials tend to preci itate or remove fromsolutlon in the oil. soluble metals resulting from the corrosion of theengine parts. The highly catalytic efiect of these metals inaccelerating oil oxidation is thus removed. These materials, also, reactwith the exposed surfaces of the engine to form thin coatings ofmaterial less readily attacked by the organic acids resulting from oiloxidation.

Another type of addition agent commonly used in highly refinedlubricating oils intended for heavy duty service is intended to preventthe formation of deposits of oil insoluble material in the various partsof the engine. longing to this class remove and prevent the formation oflacquer deposits, maintain the various oil insoluble materials in acolloidal state or as very small particles. Thus the oil insolublematerials are held in suspension in the lubricat- Materials being oilrather than being permitted to deposit on the metallic parts of theengine. The compounds commonly blended with the lubricating oil for thispurpose are oil soluble-metal containing compounds.

The usual procedure in attempting to alleviate these variousdifiiculties consists of blending with a highly refined lubricating oila mixture of these different types of additives. The active element ineach of these additives is usually incorporated in an organic compoundin order to increase the oil solubility. These various organic compoundsare substantially all less stable to oxidation than the highly refinedlubricating oil with which they are blended. The additive materialitself thus becomes the source of objectionable oxidation products. Thedegree to which these addition agents detract from the stability of thelubricating blend varies with the amount and stability to oxidation ofthe organic compounds employed.

My invention resides in the discovery that all of these beneficialeffects can be realized by blending with the highly refined lubricatingoil a small but effective quantity of metal tetrathiophosphatesubstituted with wax olefin, one to five per cent is usually sufiicient.These wax olefin substituted metal tetrathiophosphates are extremelystable to oxidation and high temperature and contain the minimum oforganic material necessary to secure oil solubility. Compounds used inthe practice of this invention are Of the types MvM'wM"zR1 (Ps4)e, MZUMIRl/(PSQ) 2, MIRMPSQE in which M, M, and M are any of the metals,aluminum, antimony, barium, cadmium, calcium, cobalt, copper, iron,lead, lithium, magnesium, manganese, mercury, nickel, sodium, tin andzinc. R is a wax olefin group. Each of "22, w, 1 and "2 is a small wholenumber from one to five inclusive.

The method of preparation of the wax olefin consists of chlorinating asubstantially oil free parafiin wax of low melting point and containingfrom 18 to 24 carbon atoms per molecule to a chlorine content of 8 to 12per cent. This is done by dispersing bubbles of chlorine gas in themelted wax at a temperature of approximately 150 F. until the desireddegree of chlorination is achieved. This is determined by the increasein Weight of the wax. This will result in a mixture of unchlorinatedwax, monochlor wax and polychlor wax. Since the greater the degree ofchlorination the lower will be the melting point of the various waxcomponents, this mixture may be easily separated to substantially purecomponents by the sweating process. fraction is preferred for theproduction of wax olefin. The monochlor wax thus obtained isdehalogenated by mixing with it one-tenth of its weight of lime andheating one to five hours at temperatures betwen 200 F. and 500 F. ThisThe monochlor 7 heating period also removes the hydrogen chloride sothat the resulting olefin is substantially free from bot chlorinated waxand hydrogen chloride.

A number of the metal tetrathiophosphates are difiicult to prepare bythe conventional procedure of heating the metal sulfides and phosphoruspentasulfide together. It has been found, however, that all of them arequite readily prepared by heating a mixture. of the metal sulfide andphosphorus pentasulfide in molten sulfur as a solvent. Since one atom ofsulfur is required for each molecule of wax olefin in the: formation ofwax olefin substituted metal tetrathiophosphate, this amount of sulfuris used as a solvent in the preparation of the intermediate metaltetrathiophosphate so that no separation isnecessary. An example of thepreparation of one: of these materials is as follows: 18 parts by weightof calcium sulfide, 56 parts by weight of phosphorus pentasulfide and 16parts by weight of sulfur were mixed and placed in a container tightlycovered to exclude air. This mixture was fused one and one-half hours at550 F. The mixture was then cooled and pulverized. This pulverizedmaterial Was then mixed with 209 parts by weight of wax olefin and themixture heated with constant stirring for one hour at 390 F. Thisproduct was oil soluble and contained 7.2 per cent ash. A thirty minutecopper strip test at 300 F. of a 2.5 per cent blend of this material inlubricating oil indicated that the material contained no uncombinedsulfur.

The choice of metal used in this composition will depend on the type ofservice for which the lubricant is intended. For service which requiresa high degree of detergency and a relatively mild control of oiloxidation and corrosion characteristics, such as is found in Diesel andCaterpillar engine operation, the preferred metal is one of the alkalimetals or one of the alkaline earth group. For service. which requiresmore oxidation and corrosion control and less detergency, such asgasoline engines in heavy-duty service, the preferred metal constituentis tin or lead. For types of service which produce excessive bearingcorrosion, the metallic element chosen should be copper. For types ofservice requiring both detergency and oil oxidation controlapproximately equally the choice of metal should be zinc. In a likemanner each of the other metals listed are valuable for specific serviceconditions.

The quantity of this material which should be blended with the lubricantwill depend upon the type of service for which the lubricant is intendedand also upon the character of the mineral oil from which thelubricating composition is made. A mineral oil which has been subjectedto a more severe refining process will require the addition of a largerquantity than a less severely refined oil. In general, quantitiesgreater than 20% will not be required, usually 10% or even beingsatisfactory for compositions requiring substantial amounts of thismaterial. Concentrations of as low as .01% will be found effective forcertain purposes.

In addition to the wax [olefin which has been referred to above, I mayemploy any long-chain hydrocarbon of petroleum origin, 1. e., as astarting material I may employ any normally liquid fraction ofpetroleum, although paramn wax is the preferable material. The processof manu-e 4 facture explained above is applicable when using anyunsaturated hydrocarbon.

Having thus described my invention I claim:

-1. A lubricating composition comprising a. mineral oil of lubricatingviscosity normally tending to oxidize in use, having incorporatedtherein from about 1% to about 5% of the productof reaction at anelevated temperature of an unsaturated hydrocarbon and the materialderived by fusing together a metal sulfide, a phosphorus sulfide, andelemental sulfur.

2. A lubricating composition comprising a mineral oil of lubricatingviscosity normally tending to oxidize in use, having incorporatedtherein from about 1% to about 5% of the product of reaction at anelevated temperature of an unsaturated hydrocarbon and the materialderived by fusing together a metal sulfide, phosphorus pentasulphide andelemental sulfur.

3. A lubricating composition comprising a mineral oil of lubricatingviscosity normally tending to oxidize in use, having incorporatedtherein from about 1% to about 5% of the product of reaction at anelevated temperature of an unsaturated hydrocarbon derived from paraffinwax and the material derived by fusing together a metal sulfide, aphosphorus sulfide, and elemental sulfur.

4; A lubricating composition comprising a mineral oil of lubricatingviscosity normally tending to oxidize in use, having incorporatedtherein from about 1% to about 5% of the product of reaction at anelevated temperature of an unsaturated hydrocarbon derived byhalogenation and de-halogenation of paraffin wax and the materialderived by fusing together a metal sulfide, a phosphorus sulfide, andelemental sulfur.

5. A lubrication composition comprising a mineral oil of lubricatingviscosity normally tending to oxidize in use, having incorporatedtherein from about 1% to about 5% of the product of reaction at anelevated temperature of an unsaturated hydrocarbon derived fromparaffinwax and the material derived by fusing together a metal sulfide,phosphorus pentasulfide, and elemental sulfur.

6. A lubricating composition comprising a mineral oil of lubricatingviscosity normally tending to oxidize in use, having incorporatedtherein from about 1% to about 5% of the product of reaction at anelevated temperature of an unsaturated hydrocarbon derived from paraflinwax and the material derived by fusing together calcium sulfide,phosphorus pentasulfide, and elemental sulfur.

'7. A composition in accordance with claim 1 in which the metal sulfideis a copper sulfide.

8. A composition in accordance with claim 1 in which the metal sulfideis a barium sulfide.

WILLIAM A. JONES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Rutherford Aug. 19, 1941

